Families of 10 of the victims of Brazil's worst air disaster have filed a US federal lawsuit against two American firms, alleging negligence.

In September, an American executive jet collided with a Brazilian passenger plane, killing all 154 people on board.

The suit names ExcelAire which operated the US jet, and Honeywell, which made some of the plane's safety equipment.

The two American pilots of the smaller jet have been held in Brazil pending the results of an investigation.

In statements to police, the pilots said they were authorised to fly at 11,200m (37,000ft) - the same altitude as the Boeing passenger jet.

Although the crash damaged the wing and tail of the private jet, the New York pilots managed to land safely and all seven people on board survived.

An earlier death toll of 155 for the passenger plane was revised downwards by the airline, after it was found that one passenger had been listed twice.

'Gross negligence'

In the lawsuit, the families allege that the ExcelAire jet's pilots were flying at an incorrect altitude and the transponder - a piece of equipment used for gauging an aircraft's position - was not working at the time of the crash.

Honeywell, the firm that manufactured the transponder, has said that it is not aware of any evidence to show that was the case. ExcelAire is yet to comment.

The lawsuit, which seeks unspecified damages, accuses both companies of gross negligence.

"The negligent acts and omissions of ExcelAire and its pilots... were a substantial contributing factor to the mid-air collision," said Robert Lieff, whose law firm is representing the families.

"Honeywell shares responsibility for the collision and the wrongful deaths of the plaintiff's decedents because it defectively designed the transponder," he said.

The Boeing 737 was flying from Manaus to the capital, Brasilia, when it vanished from radar screens in the Amazonian state of Mato Grosso.